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51.
Donnelly RF Morrow DI McCarron PA David Woolfson A Morrissey A Juzenas P Juzeniene A Iani V McCarthy HO Moan J 《Photochemistry and photobiology》2009,85(1):195-204
Silicon microneedle (MN) arrays were used to puncture excised murine and porcine skin in vitro and transdermal and intradermal delivery of meso-tetra ( N -methyl-4-pyridyl) porphine tetra tosylate (TMP) investigated using topical application of a bioadhesive patch containing 19 mg TMP cm−2 . Animal studies, using nude mice, were then conducted to investigate the in vivo performance of the bioadhesive patch following MN puncture of skin. MN puncture significantly enhanced both intradermal and transdermal delivery of TMP in vitro , though the total amounts of drug delivered (25.22% into porcine skin and 0.07% across murine skin) were still quite small in each case. Notwithstanding this, in vivo experiments showed that MN puncture was capable of permitting a prolonged increase in TMP fluorescence at the site of application. Importantly, fluorescence was negligible at distant sites, meaning systemic delivery of the drug was not sufficient to induce TMP accumulation other than at the application site. In this study we have conclusively demonstrated proof of principle; MN puncture allows true intradermal delivery of a preformed photosensitizer in animal skin models in vitro and in vivo . Importantly, transdermal delivery was much reduced in each case. Increasing MN density would allow increased amounts of photosensitizer to be delivered. However, as MNs create aqueous pores in the stratum corneum, a preformed photosensitizer must possess at least some degree of water solubility in order to permit enhanced intradermal delivery in this way. We believe that use of MN array technology in this way has the potential to significantly improve topical photodynamic therapy of skin tumors. 相似文献
52.
Samaneh Abbasi Pierre J. Carreau Abdessalem Derdouri Michel Moan 《Rheologica Acta》2009,48(9):943-959
This paper is concerned with several issues related to the rheological behavior of polycarbonate/multiwalled carbon nanotube
nanocomposites. The composites were prepared by diluting a masterbatch of 15 wt.% nanotubes using melt-mixing method, and
the dispersion was analyzed by SEM, TEM, and AFM techniques. To understand the percolated structure, the nanocomposites were
characterized via a set of rheological, electrical, and thermal conductivity measurements. The rheological measurements revealed
that the structure and properties were temperature dependent; the percolation threshold was significantly lower at higher
temperature suggesting stronger nanotube interactions. The nanotube networks were also sensitive to the steady shear deformation
particularly at high temperature. Following preshearing, the elastic modulus decreased markedly suggesting that the nanotubes
became more rigid. These results were analyzed using simple models for suspensions of rod-like particles. Finally, the rheological,
electrical, and thermal conductivity percolation thresholds were compared. As expected, the rheological threshold was smaller
than the thermal and electrical threshold. 相似文献
53.
PORPHYRIN PHOTOSENSITIZATION AND PHOTOTHERAPY 总被引:11,自引:0,他引:11
54.
An ethylene glycol/water glass containing the chromophore L-tryptophan and the electron scavenger CCl3COONa was exposed to 254 and 310 nm UV light and to γ-rays and studied by ESR methods. The total yield of radicals per absorbed quantum of radiation increases with increasing scavenger concentration. This increase is attributed to the ability of the scavenger to prevent electrons from recombining with their parent cation. The recombination probability of ejected elec- trons was estimated to 0.8 in the case of UV-induced ionization and 0.4 in the case of γ-induced ionization. 相似文献
55.
Study of the dependence on concentration of the reduced viscosity of carboxymethylcelluloses (CMC), in the absence of added salts and down to relative viscosity 1·-01, leads to two typical parameters of the polyion. The molecular dimensions of H-CMC and Na-CMC have been determined from these two parameters using a rod-like model. The gradient dependence of viscosity has been studied; the two samples of CMC in water (M = 41,000 and 180,000) show the non-Newtonian behaviour of solutions of rigid particles. 相似文献
56.
57.
Kristian Berg Jerry C. Bommer James W. Winkelman Johan Moan 《Photochemistry and photobiology》1990,52(4):775-781
The cellular uptake, relative fluorescence quantum yields and photosensitizing efficiencies of meso-tetraphenylporphines sulfonated to different degrees (TPPSn) have been investigated using the human carcinoma cell line NHIK 3025. The efficiencies of these dyes in photoinactivation of cells were highly dependent on the number of sulfonate groups on the derivatives. These differences in phototoxicity were primarily due to different abilities to be taken up by cells, but were also dependent upon the cellular localization of the dyes. TPPS1 and TPPS2a were more efficiently taken up by the cells than TPPS2o and TPPS4. Plasma membrane associated TPPS4 was less efficient in cell inactivation per quantum of fluorescence emitted than intracellularly located dye. This was also to some extent the case for TPPS1 but not for TPPS2a and TPPS2o. The results presented here indicate that TPPS2a and TPPS1 are the most promising of the TPPSns for possible future use in photodynamic therapy. 相似文献
58.
Abstract— Human cells of the line NHIK 3025 were exposed to hematoporphyrin derivative (Hpd) and light and analysed with respect to; (i) the mobility of membrane proteins as determined by electron spin resonance measurements of a protein-bound spin label, (ii) fluorescence excitation spectra, (iii) relative number of DTNB-reactive SH-groups on their surface and in sonicated cell homogenates, (iv) survival, and (v) morphologic appearance as seen by ordinary phase contrast microscopy. A significant fraction of the porphyrins bound to the outer cell membrane was in close contact with proteins. 5,5'-Dithiobis-2-nitrobenzoic acid reactive SH-groups on the outer cell membrane were very sensitive to the treatment with Hpd + light and were degraded according to non-exponential kinetics. When the cells were irradiated after spin labelling, the labelled proteins became less mobile during the irradiation, indicating protein cross linking. Irradiation before spinlabelling resulted in a selective degradation of low-mobility proteins. 相似文献
59.
van den Akker JT Iani V Star WM Sterenborg HJ Moan J 《Photochemistry and photobiology》2002,75(2):172-177
Topical application of 5-aminolevulinic acid (ALA) for protoporphyrin IX (PpIX)-based photodynamic therapy of skin cancer is generally considered not to induce systemic side effects because PpIX is supposed to be formed locally. However, earlier studies with topically applied ALA have revealed that in mice PpIX is not only produced in the application area but also in other organs including skin outside the application area, whereas esterified ALA does not. From these results, it was concluded that it is not redistribution of circulating PpIX that causes the fluorescence distant from the ALA application site, but rather, local PpIX production induced by circulating ALA. In the present study we investigate the effects of the ALA concentration in the cream, the application time, the presence of a penetration enhancer, the presence of the stratum corneum and esterification of ALA on the PpIX production in nude mouse skin outside the area where ALA is applied. For this purpose, ALA and ALA hexyl ester (ALAHE) were applied to one flank, and the PpIX fluorescence was measured in the contralateral flank. During a 24 h application of ALA, PpIX was produced in the contralateral flank. No PpIX could be detected in the contralateral flank after ALA application times ranging from 1 to 60 min. Tape-stripping the skin prior to short-term ALA application, but not the addition of a penetration enhancer, resulted in PpIX production in the contralateral flank. When ALAHE was applied, no PpIX fluorescence was measured in the contralateral flank under any application condition. The results suggest that the systemic component of PpIX production outside the ALA application area plays a minor or no role in relevant clinical situations, when the duration of ALA (ester) application is relatively short and a penetration enhancer is possibly added. 相似文献
60.
Nielsen KP Juzeniene A Juzenas P Stamnes K Stamnes JJ Moan J 《Photochemistry and photobiology》2005,81(5):1190-1194
We have investigated the role of tissue oxygenation on light penetration into tissue at different wavelengths. As a field of application we have chosen aminolevulinic acid-photodynamic therapy (ALA-PDT). To calculate efficiency spectra of PDT on human skin one needs to know the excitation spectrum of the photosensitizer of interest and the relative fluence rate as a function of depth in the tissue. We measured the former and computed the latter with an accurate radiative transfer algorithm. In this way we determined the efficiency spectra as functions of depth for different types of basal cell carcinomas (BCC). Our results suggest that ALA-PDT works best for nodular BCC at a wavelength of 630 nm, whereas it works best for pigmented superficial BCC at a wavelength of 390 nm. At 630 nm the light penetration into a tumor depends strongly on the oxygenation of the blood. Below a 2 mm thick, well-oxygenated, nodular BCC, we find the efficiency to be an order of magnitude larger than below a poorly oxygenated tumor. At 390 nm, the light penetration into a tumor does not depend on the oxygenation of the blood. 相似文献